1. Increasing Diversity of Native Biofuel Plantings Using Simple Mixtures
Cody Zilverberg1,2, Kwan Teoh1,
W. Carter Johnson1, Arvid Boe1, Vance Owens3
1South Dakota
State University
2Texas A&M
AgriLife
Research
3North Central
Regional
Sun Grant Center
Tallgrass prairie in SD recently being converted to cropland
Our research group interested in getting some of that land back into native perennial plants
Biofuels may be one way
photo: Craig Novotny

2. Biomass biofuel visionX O
Increase diversity of cellulosic feedstock
Improve ecosystem services
Maintain or increase yield
Costs and management might also increase

3. Question
Can other prairie plants outyield switchgrass at specific topographic positions?

4. treatments
differed
Figure Mean biomass of ‘Sunburst’ switchgrass and a big bluestem-dominated mixture (‘Bluestem’) from 2009 to Plots were cut at 10 cm from 2009 to 2011 and at ground level from 2012 to Adjacent plots of ‘NE28’ switchgrass were also sampled in 2013 and 2014 and are included for comparison, but they were not included in the statistical analysis. Sunburst differed from Bluestem in 2009 and 2010 only. The least significant difference for comparing two years within the same species was 1.81 Mg / ha.

6. Canopy cover 2014

7. Site & treatments eastern South Dakota formerly corn-soybean field
silt loam, silty clay loam, gravelly loam
3 blocks
plot size: ~ 1m2
from CIG report: “Wentworth and Egan upland soils while two replications included the relatively lower producing Dempster and Talmo soils with lower water holding capacities. The lower parts of the landscape are dominated by poorly drained Worthing and Baltic soils that are often associated with spring flooding and seasonal wetlands.”

8. Site & treatments Topographic position Species Mix ratio
shoulder slope
midslope
footslope
Species
monocultures & binary mixtures w/ switchgrass
Mix ratio
0 % (switchgrass monoculture)
33 % companion
67 % companion
100 % companion (companion monoculture)

9. Experiment 1
Species at each slope position. Sunburst switchgrass at all slope positions
Slope position
C4 grass
C3 grass
Forb
Shoulder
‘Badlands ecotype’
little bluestem
(Schizachyrium scoparium)
‘Lodorm’
green needlegrass (Nassella viridula) †
purple prairie clover (Dalea purpurea)
Mid
‘Sunnyview’
big bluestem
(Andropogon gerardii)
‘Primar’
slender wheatgrass
(Elymus trachycaulus)
‘Sunrise’
canada milkvetch (Astragalus canadensis)
Foot
‘Prairie Farm’
prairie cordgrass
(Spartina pectinata)
‘Rodan’
western wheatgrass (Pascopyrum smithii) ‡
cup plant
(Silphium perfoliatum)
†Natural germplasm from the Bismarck Plant Materials Center
‡ Population developed at South Dakota State University
3 blocks
From shoulder slope to foot slope, mean distance and elevation change were 52 m and 2.33 m, respectively

10. 2013

11. 2013

12. Shoulder slope (2013-2014) Little bluestem Green needlegrass
Purple prairie clover
Switchgrass
2013-4
Bars with the same lowercase letter are not significantly different (p > 0.05)

13. 2014 midslope of block 3

14. Mid slope 2013 Big bluestem Switchgrass Canada milkvetch
Slender wheatgrass
2013
Bars with the same lowercase letter are not significantly different (p > 0.05)

15. Mid slope 2014 Big bluestem Switchgrass Canada milkvetch
Slender wheatgrass
2014 footslope of block 3
Bars with the same lowercase letter are not significantly different (p > 0.05)

17. Foot slope 2013 Prairie cordgrass Cup plant Switchgrass
Western wheatgrass
2013
Bars with the same lowercase letter are not significantly different (p > 0.05)

18. Foot slope 2014 Prairie cordgrass Cup plant Switchgrass
Western wheatgrass
2014
Bars with the same lowercase letter are not significantly different (p > 0.05)

19. On the landscape – max biomass
Prairie
cord-
grass
67% Little
blue-
stem
Switch
Big
blue-stem
plant
Switch
Switch
2013

20. Conclusions
High-biomass alternatives to switchgrass exist at all landscape positions
Mix-and-match species to balance goals for biomass and biodiversity

21. Acknowledgements
North Central Regional Sun Grant Center at South Dakota State University through a grant provided by the US Department of Energy Bioenergy Technologies Office under award number DE-FG36-08GO88073.
Craig Novotny
Student workers

22. Cuplant/switchgrass mixture 2013

23. Historic tallgrass prairie (Weaver, 1968)
Basal Area *
Historic tallgrass prairie (Weaver, 1968)
10-15% 13% * * * * * * * *
Shoulder
Midslope
Footslope
* For this species, 2013 differs from 2014 (p < 0.10)

24. 2013 Monocultures Switchgrass 2013.
Correlation of companion and switchgrass deviations was 0.07 (p = 0.64) in 2013 and (p = 0.057) in 2014.
When green needlegrass was excluded from the dataset, correlations were (p = 0.01) in 2013 and (p < 0.001) in 2014.
Switchgrass

25. Like previous slide but for 2014** *
Correlation of companion and switchgrass deviations was 0.07 (p = 0.64) in 2013 and (p = 0.057) in 2014.
When green needlegrass was excluded from the dataset, correlations were (p = 0.01) in 2013 and (p < 0.001) in 2014. * **
* significant at p < 0.10; ** significant at p < 0.05

28. Historic tallgrass prairie (Weaver, 1968)
Basal Area
Species
Year
p-value
Historic tallgrass prairie (Weaver, 1968)
Shoulderslope
2013
2014
Purple prairie clover 5 7
0.09
10 – 15%
Green needlegrass 11 14
0.13
Little bluestem 15 21
0.02
Switchgrass 26
0.01
Midslope
Canada milkvetch -
13%
Slender wheatgrass 9 19
0.16
Big bluestem 10 16
0.04
Footslope 
Cup plant
0.03
Western wheatgrass
43 (8)
69 (23)
0.16 (0.03)
Prairie cordgrass
28 (0)
65 (14)
0.02 (0.02)

29. Shoulder slope Little bluestem Switchgrass Purple prairie clover
Green needlegrass
2013

30. Mid slope Big bluestem Switchgrass Canada milkvetch Slender wheatgrass
2013

31. Foot slope Prairie cordgrass Cup plant Switchgrass Western wheatgrass
2013

32. More monocultures?
Society increasingly demands “multi-functional” agriculture
‘Maximum-yield’ and ‘maximum short-term profitability’ paradigms fall short
image: Laurence Packer
photo: D. Gordon E. Robertson

33. More monocultures?
If cellulosic biofuels are successful, will we just create more monocultures (switchgrass?) to replace current biofuel monoculture (corn)?
image: MS clipart
clover photo: Ben Cox

34. Alternative vision Increase diversity of cellulosic feedstockX O
Increase diversity of cellulosic feedstock
Could be achieved at multiple scales
Improve ecosystem services
Maintain or increase yield
Costs and management might also increase

35. Establishment & management
Plugged June 2012
Weeded as needed